On the OpenVPN Server with IP you need to add a route to the network behind the OpenVPN client (10.0.8.2)
On OpenVPN Server go to custom Options and add:
route 192.168.120.0 255.255.255.0;
Probably you do not need this entry because you entered this network in "Remote Network" in the OpenVPN Server options.
On the client OpenVPN add this:
route 192.168.0.0 255.255.255.0;
iroute 192.168.120.0 255.255.255.0;
Check and allow traffic on bothe firewalls for OpenVPN.
For testing purposes a simple "Allow any to any" rule should work.